Preachers caught squatting in white spaces

The Wireless Innovation Alliance has written an open letter to the FCC accusing US churches, clubs and events of illegally operating in the white space they want for themselves - though it says it's prepared to compromise in exchange for access.

The letter (pdf) comes as part of evidence presented to the FCC in the ongoing debate on use of white space, and in response to presentations from wireless-mic-manufacturer Shure which is siding with TV broadcasters in an attempt to keep white spaces white.

In the US wireless microphones frequently operate in spectrum used for TV broadcasting. Despite the broadcaster holding a national licence transmitters operate on different frequencies to ensure coverage. This leaves gaps where low-power applications, such as wireless mics, can operate without generating interference - gaps known as "white spaces".

Broadcasting in white space is technically illegal, even for a wireless microphone, but as long as no-one suffered too much interference it's never been an issue before. But now companies including Google and Microsoft are seeking to exploit that space using devices which they claim can automatically identify white spaces and avoid interfering with TV broadcasts. But avoiding wireless microphones isn't so easy.

So the alliance is suggesting that every wireless microphone be fitted with a beacon to advertise its presence and allow nearby white-space kit to avoid interfering with it. Shure estimated that this would add $1,000 to the cost of every mic, a claim ridiculed in the letter.

"Shure’s estimate of equipment prices approaching $1,000 per beacon is wildly inaccurate. Preliminary designs lead Coalition engineers to estimate the cost ... will be only $40 to $50 and, in large quantities, could be in the range of $10."

But the alliance also wants to see wireless mic users required to get an FCC licence, something which will surely see sales of wireless mics dropping off and something Shure will be keen to avoid.

In the UK there aren't so many white spaces, but Ofcom has identified 81 patches of what it calls "geographically interleaved spectrum", and has launched a consultation on the best way to sell licences to use them - not quite what Google or Microsoft et al had in mind. ®